text:
Why can’t aircraft use GPS to generate the IAS, instead of using pitot tubes?
I’m mostly asking after reading about Aeroperu Flight 603, which was caused by a piece of tape blocking the sensor. Is there any other way to gather IAS or is this the best way to do it?

Because GPS captures groundspeed, not airspeed.

@Pondlife yes it did. Thank you!

His question had two parts.  The linked answer only covers the first part.  My answer here covers the second.

To answer the other part of your question, in a scenario where you lose all 3 speed indications, you are left with pitch and power.  If you know the airplane really well and are sufficiently skilled at flying, this should be enough.
For example if you've been flying some jet for a while you will know that at Vref on a 3 degree glide slope flaps and gear down you will have an fan RPM range of say 60% at lighter weights and 65% at max landing weight.  So when on the glide slope you just hold the pitch attitude that keeps you on slope and keep the power there and the speed will take care of itself, within reason.
Same if you're just flying around in level flight.  Just holding the pitch attitude and setting power at the value you're used to will keep your speed somewhere in the ballpark.  In fact, at the extremes, it's quite easy to tell the difference between 250 kt and 330 kt just from the sound (the roar at Vmo is unmistakable).
On a descent at idle, you'll know from experience that the pitch attitude is, say, 15 degrees below the horizon at 200 kt.   So you just fly the attitudes you know will work, with power that's appropriate to the speed range you want, and you'll be close enough not to fall out of the sky.
On top of that, the manufacturers all provide pitch/power setting tables in their QRH procedures that can be used to maintain speeds close enough to avoid falling from the sky (fallout from some of the clear-air pitot icing incidents).
I know personally of an Atlantic Southeast Airlines CRJ crew that lost all 3 airspeed inputs from ice crystals, used their pitch/power skills to manage things on decent until they got their speed indications back when they were lower.  But they would have had no problem landing the plane with no airspeed if it came to that, and that was before there were QRH pitch/power tables.
The Aeroperu guys were unfortunate in that they went into brain-lock and became disoriented in the darkness.


text:
Is this a video of severe turbulence for an Airbus A320? (video)

I remember reading that in 1966, a 707 encountered turbulence and the wings and tail were torn off (BOAC 911). Is this video at all comparable? Is the A320 more robust than the 707?

"a 707 encountered this exact type of turbulence" how can you be sure that is was the "exact type of turbulence"? and of the same strength/intensity?

Winds at the peak of Mt. Fuji were recorded at around 60-70 knots. (70-80 mph). BOAC 911 was at around 16,000 feet where the air is about half as thin as the altitude this flight was at (close to sea level; coming in to land), and they registered over 50 miles an hour at sea level. I'd say the intensity of loads put on the fin was comparable when accounting for air density.

@Warden A constant wind does not put any load on a wing because the aircraft flies within the moving air. Only wind speed (or direction) changes (turbulence) are relevant.

Sorry, I made a mistake, I was referring to gusts.

without any numbers and sources, that's just speculation and wishful thinking.

Given that BOAC 911's FDR couldn't be retrieved, all we can do is speculate. Even the Wikipedia article is mostly speculation due to lack of FDR data. This was back in 1966.

There is no evidence what happened in the video was caused by turbulence. If you look at the flight control surfaces, it appears it was all a result of pilot control inputs. Nothing in that video would even suggest a structure failure was imminent.

If aircraft were built so they would fall apart every time they wobbled from side to side a bit, I doubt the aircraft industry would be as successful as it is today-

The video refers to BA492 on Feb. 25th.  Here is more info:
https://www.aviationcv.com/aviation-blog/2019/british-airways-flight-ba-492-extreme-wind

I think this question seems reasonable, on topic, clearly written, and interesting, so I'm giving it an upvote.

@abelenky Does your edit reflect the intention of the QE? And isn't it a bit fishy to adapt the question to your own answer? Just wondering...

Possible duplicate: What is the cause of this roll oscillation during BA492 go-around? (closed)

That is not strong turbulence.
It is not strong turbulence because the passenger keeps both feet on the floor, and is able to hold his phone relatively steady.
In severe turbulence, everything is thrown around the cabin:  bins pop open, cell phones are ripped from hands and become projectiles, luggage flies across the plane, people are thrown to the ceiling if not buckled in, and if they are buckled in, their knees hit their chest with considerable force.  In severe turbulence, broken bones, concussions, and spinal injuries are common.
Even in those conditions, airplanes do not break apart.  Turbulence strong enough to destroy an airplane would leave everyone inside the plane, including the pilots, unconscious and severely injured.
That the passengers on this flight could speak, sit upright, and film indicates that this turbulence was mild-to-moderate at worst.

Think of severe turbulence like this:
Have you ever been in a relatively low-speed car crash (around 20-30 MPH), where the airbags go off, the glove box pops open, you hit your arms on the dash, and everything loose in the car goes flying?
Severe turbulence is like being on an amusement park roller-coaster, with lots of shaking, dives, climbs, and turns while also being in a car crash every 10 seconds.  The average turbulence is shaking you around constantly so all you can do is hold on, and several times a minute you also get a big jolt similar to a car crash!

It did not break up, because it is designed and built strong enough to withstand this kind of load - and quite a lot more.
Aircraft wings also have to pass wing bending stress tests. Here is a catchy video on bending the wings of an A350.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


text:
Is a pilot responsible for CTAF announcements in this scenario?
A Cessna 525 Citation Jet is coming in to land and a single-engine Cessna 150 is taking off at a small airport with no ATC. The Cessna 150 stays in continued radio contact and the Cessna 525 Citation Jet does not.
An accident occurs where the Cessna 150 clips the Cessna 525 Citation Jet on the tail end. The Cessna 150 crashes and burns. The people in the Cessna 150 pass away and no one is injured on Cessna 525 Citation Jet.
Is this labeled as an accident although the Cessna 525 Citation Jet did not stay in radio contact after landing when the Cessna 150 attempted to take off?
https://www.cbsnews.com/news/marion-indiana-airport-planes-collide-2018-04-02/

Possible duplicate of What is the difference between aviation "accident" and "incident"?

Welcome to aviation.SE!

What does the word "accident" mean to you?  I am guessing it has some legal meaning for you, perhaps an assignation of liability.  In aviation, however, "accident" merely means that something seriously bad happened, without regard to blame.  At least in the U.S.

You claim that the 150 stayed in continued radio contact, but it is unclear who you think they were in radio contact with.
Clearly not the jet, as you say the jet was not in contact... and again: Not in contact with who?  Radio communication requires two parties.

I'm voting to close this question as off-topic because the question is about how the incident will be labelled and the investigation is on-going. We've discussed in Meta that accidents will not be discussed until the investigation is completed.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
What are the effects of the tilted lift vector in a banked plane?
I want to clarify the effects of the change in direction of the lift vector caused by banking in a plane.
Banking rotates the lift vector creating a horizontal component. I have read that some effects of this horizontal component are as follows:
1) It acts as a centripetal forcing inducing circular motion in the plane.
2) It generates sideslip such that in dihedral planes there is an increased angle of attack in the lowered wing, and a decreased angle of attack in the raised wing. This generates a restoring moment facilitating roll stability.
So my questions are as follows: How does the horizontal component of the lift have both a centripetal effect and a slide slip effect? (A more general question) In a banked turn under cetripetal force, what causes the change in the heading of the plane such that its longitudinal axis remains facing the relative wind?
Perhaps I have somewhat answered the first question with the second: initially under the centripetal force the plane does not yaw to have its longitudinal axis aligned with the new air velocity vector and therefore sideslip occurs? I am not sure, please let me know.
Thanks

" there is an increased angle of attack in the lowered wing, and an increased angle of attack in the raised wing. " - I think there is a decreased angle of attack in the raised wing

Quite right, a lack of concentration...

That is why you can edit your question.  I fixed it for you. (you should have fixed it yourself)

I was just asking myself this and question today while reading my PPL book.

Highly related -- https://aviation.stackexchange.com/q/102352/34686

In a banked turn under cetripetal force, what causes the change in the heading of the plane such that its longitudinal axis remains facing the relative wind?

The simplest case of a flat wing will create lift orthogonal to its direction of motion and the direction of wingspan, and some drag parallel to its direction of motion. Both lift and drag will act in the plane of symmetry. Let's assume that drag is compensated by a constant thrust, so the level wing is in equilibrium. A tilt will contribute a sideways lift component that is not compensated by weight and will accelerate the wing sideways.
This will move the wing into the direction of lift and reduce its angle of attack. Lift will drop which reduces sideways acceleration. Unfortunately, this also means that gravity will not be fully compensated. The wing will be accelerated downwards which increases its angle of attack. Both effects will settle at a point where the wing moves side- and downwards, the sink speed depending on the drag increase since more lift in total must be generated.
But the picture is incomplete without the contribution of the tail surfaces. The sideways motion will cause a side force on the vertical tail which will weathervane the aircraft into the direction of sideslip. Only that lateral stability contribution will start the turning motion. Now you get a continuous process in which the wing accelerates the whole airplane sideways and the tail will yaw it into the wind, resulting in a not well coordinated turn. The yawing motion will add a centripetal acceleration which will eventually balance the sideways acceleration from the tilted lift force.
Since we decided to leave thrust constant, the added lift requirement will cause more drag and the aircraft will sink in order to compensate for the energy loss from turning. If we now add the freedom to change the elevator deflection, we can trim the aircraft for the higher lift and a lower speed so that (depending on the position of the initial state on the power curve) the aircraft could fly a level turn at a lower flight speed.
I also neglected pitch stability so far. At higher bank angles it becomes important and contributes to the turn in proportion to the sine of the roll angle. With a constant elevator deflection, pitch stability will try to keep speed constant and pitch damping will reduce the turn rate. Once we allow to adjust the elevator, pulling will reduce pitch damping and trim a higher angle of attack, so the turning rate will pick up.

In straight flight, the lift is not causing any rotation of the aircraft. When you start a bank (using ailerons), the centre of lift does not move, only the direction changes, so the plane does not yet start turning, it starts to side-slip (effect 2).
Now the side-slip has two effects:

It changes lift differently on the windward and leeward wing. The effect is rather complex depending on wing position and dihedral, but generally aircraft are designed so the result is slightly restoring.
It creates a side force on the vertical stabiliser that will turn the aircraft towards the relative wind (weathervaning).

And only now when the aircraft started turning, the lateral component of lift will provide the centripetal force to sustain the turn (effect 1).
Of course in practice it does not occur in distinct steps. As you start rolling, the side-slip will start developing, but it will be immediately causing yaw, so not much side-slip develops.
Or the pilot (or yaw damper) will do their job properly and work the rudder to initiate the turn together with banking, avoiding the side-slip altogether.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Can I fly under a solar eclipse to lengthen its effect?
There is going to be a solar eclipse in 2017 and I thought it would be cool to fly along its path to make it longer than the approximately two and a half minutes you would see on the ground.
Is this a bad idea?
Should I go to fast or slow for the solar eclipse?
I think it would be fun to fly during the solar eclipse, even if I can't keep pace with it.

There is no regulation (in the US) preventing you from flying "under" a solar eclipse. Night flying regulations do not apply in this case so you don't need to be night current. You will not be keeping pace with it though, you may extend it by a few seconds, but not significantly.

Or perhaps you could persuade an airline to participate to the event: Alaska Airlines adjusts flight plan to delight astronomers. At least you will be over the clouds. Be sure to have a seat on the good side though :-)

Hopefully you would be concentrating on flying the airplane rather than looking at the solar eclipse.

https://wiralfeed.files.wordpress.com/2015/10/sun-eater1.jpg

This article might interest you : "Flight to Totality: How I Chased the Total Solar Eclipse of 2015 on a Jet"

Very related.

It is possible. The shadow of the moon goes too fast to keep up with that, but there are other reasons to do it. Firstly, when you fly over the clouds, you can be sure they don't obstruct your view. Second reason is that sometimes solar eclipse, or the best part of it, only appear over an ocean.
Here is an article from last year. Couple of interesting quotes from it:
"Taking to the skies during the sun being eclipsed out of view behind the moon, is not a new concept. In fact in 1887, Dmitri Mendeleev, the Russian inventor, was so keen to see the eclipse without cloud obstruction that he rode in a hot air balloon when it took place."
"In the past private operators have capitalised on the event by offering special eclipse flights."
http://www.dailymail.co.uk/travel/travel_news/article-3475224/Out-world-best-commercial-flights-witnessing-total-solar-eclipse.html


text:
What does "Zero for twenty" mean?
In Top Gun (1986), a flight got hit by a missile:

Pilot: I'm hit! I'm hit! We're coming apart! I can't control it! Hold on!
Zero for twenty! We're going down!

What does "Zero for twenty" mean?

I don't remember that line, could not find it in scripts (this and this) either. Can you share the video?

The scene is here: https://www.youtube.com/watch?v=mM3fHmmHovg time 8seconds.
I believe the real line is "Zero Four Twenty We're going down", as in "Tail Number #0420 is going down" (but just my personal opinion, I don't have a source)

After multiple replays, I might also hear "Oh-Nine-Zero-Four-Twenty  We're going down" (090420) instead of "hold on 0420".

The line said in the movie is "090 for 20", and he is calling out his relative position.
It is in a standard format for a range and bearing callout, with the 090 being magnetic bearing and 20 being nautical miles.
The clip is too short for the context, but range and bearing could be from the ship, from an arbitrary pre-briefed "bullseye" location, or from the engaging fighter itself.
SHIP:  If they were using the ship as a reference point a quick check of the TACAN is all that's needed.  In this case the tail of the needle, or radial, would be at 090 and DME would read 20.  A combat engagement 20 NM from the ship is VERY close, so they were probably using...
BULLSEYE: In the more likely event that the ship is controlling electronic emissions and the TACAN is off, a mission cycle will assign an arbitrary Latitude/Longitude as "bullseye".  This bullseye point then becomes the center of an imaginary VORTAC in the middle of the ocean.  All aircraft on that mission cycle will enter this location in their navigation systems and reference their position off it as if it were a real navaid.
In this case the hit pilot is obviously calling out his position relative to whatever anchor point they have chosen to use as a reference on this mission to get help on the way.
If, (in the case of the last example) the transmission were coming instead from a tactical controller onboard the ship or from AWACS, the call would be for the engaging fighter to help get their radar on the target.  For example, "Maverick, bandit at your 090 for 20."

I've always used the term "at" for DME, not "for".   I would say I'm "Bearing 090 at 20".   Interesting use of "for" in this case, especially since its a homonym with "four(4)".

@abelenky, I guess I hadn't thought too critically about it before, but you are absolutely correct. Just one of those cultural bits of lingo that you get used to. And I'm sure "at" was used sometimes as well...


text:
Is there any position I can get gps signal on Boeing 787?
As an aviation enthusiast, I use some apps like garmin pilot to capture gps signal on planes to track plane routes.
But I found that I can't get any gps signal on 787. I guess the reason is the material of the electronic dimming system. Is there any position in the cabin to get a better gps signal?

The fuselage of the 787 is entirely made from carbon laminate as can be seen in this picture (taken from here):

Cabon fiber blocks GPS and other radio signals pretty well. So unfortunately no, there is no part of the fuselage which offers better GPS reception. You could try to push the antenna agains the window, perhaps the GPS-Tracker has better luck picking up a signal there...

And to make matters worse, there's a copper mesh embedded in the composite for lightning protection.

@u_flow I tried to put antenna against the windows. But no luck


text:
What is “abnd” on the U.S. VFR Sectional Chart?
I have looked at the sectional legend and FAA aeronautical chart user guides and have not seen any answer for this.
What is “abnd” on the U.S. VFR Sectional Chart?

It's not on the abbrevations list, but I would assume that it is indicating that the railway is an abandoned line.

That example is a railroad, and it is "abandoned".   That means it won't make a very good Iron Compass, as it is won't have the impeccable tree trimming, clean ballast and weed spraying that makes railroads so visible normally.
It may well be that the rails are in place and is merely embargoed, little-used or in preservation, but that is of little concern to aviators.
Of concern is that the indicated river bridge, that you've been using as a landmark, may not be there anymore.


text:
What is timed approach?
I have tried to find what timed approach is, but I cannot find any reference to it. Could you let me know what it is and when it is used?

I had never heard of this or seen an approach with a holding fix at the FAF or outer marker when I ran across a question on timed approaches from a holding fix in Gardner’s Complete Advanced Pilot. As you can see from the quotes at the bottom of the post, it is unlikely to ever be used. But they are still available to the controller, FAA Order JO 7110.65W Air Traffic Control.
FAA_H_8083-15B Instrument Flying Handbook 2012
Timed approaches from a holding fix are conducted when many aircraft are waiting for an approach clearance. Although the controller does not specifically state “timed approaches are in progress,” the assigning of a time to depart the FAF inbound (nonprecision approach), or the outer marker or fix used in lieu of the outer marker inbound (precision approach), indicates that timed approach procedures are being utilized.
In lieu of holding, the controller may use radar vectors to the final approach course to establish a distance between aircraft that ensures the appropriate time sequence between the FAF and outer marker or fix used in lieu of the outer marker and the airport. Each pilot in the approach sequence is given advance notice of the time they should leave the holding point on approach to the airport. When a time to leave the holding point is received, the pilot should adjust the flightpath in order to leave the fix as closely as possible to the designated time.
Timed approaches may be conducted when the following conditions are met:

A control tower is in operation at the airport where the approaches are conducted.
Direct communications are maintained between the pilot and the Center or approach controller until the pilot is instructed to contact the tower.
If more than one MAP is available, none require a course reversal.
If only one MAP is available, the following conditions are met:
a) Course reversal is not required; and
b) Reported ceiling and visibility are equal to or greater than the highest prescribed circling minimums for the IAP.
When cleared for the approach, pilots should not execute a procedure turn.

The actual order specifies that Timed approaches using either nonradar procedures or radar vectors to the final approach course may be used at airports served by a tower if the following conditions are met and goes on to give similar conditions.
The AIM has an example of how they might be used.

The sons of the guys who wrote that procedure are now in the “Old Controllers’ Home”, I can only guess at their intent. The last time I had to run timed approaches was when I was taking non-radar problems to certify on Denver Sector 26 (COS/PUB low) in 1968! R Butler – ATC Controller
We did some timed approaches when I worked a U.S. non-radar approach control in the ’80s. Don’t believe there are any non-radar approach controls left, and I don’t know a single radar controller who would try it if there were a radar outage of some sort. We also had to run them at the FAA Academy in training back in the ’70s. You would need to assign different missed approaches to succeeding aircraft, so #2 doesn’t catch #1 on the miss.
It’s a lot of radio and brain work to do successfully. Non-radar at a radar facility, (because of an outage) is usually very limited now. (One in, one out) Backup radar systems preferred, even if not as accurate. vector4fun

if the last paragraphs are quotes, could you put them in quoteblocks, and possibly provide the sources?

I cannot disagree with any of the above, but I'm not sure it really addresses the question.  There are a great many published non-precision VOR and NDB approaches that involve a timed procedure turn, followed by starting the clock when a fix is crossed, and executing a missed approach based on elapsed time.  (for a given airspeed)  Is this what the OP was asking?  Because I can provide a more detailed answer... (but I'm not sure how to post pictures in an answer)

Actually, there is a perfect example of timing from the Final Approach Fix, (FAF) to the Missed Approach Point, (MAP) of 4.4 NM in the lower right corner of the ILS LOC rw 7 approach depicted above.  Depending on the airspeed being flown the time to the MAP is shown on the second row.  For aircraft without distance measuring equipment the pilot would rely on timing to know when the MAP was reached.  I would be happy to post this as an answer, but I do not know how to add a picture, and don't want to refer to another answer in case it is later deleted.

@MichaelHall That's not the same thing as a timed approach

@TomMcW, it isn't obvious to me what the OP was asking.

@MichaelHall "Timed approach" is an IFR procedure listed in in the AIM. It specifically means what this answer is addressing.

Got it, thanks.  Looks a lot like aircraft carrier Case III procedures.


text:
Why does aviation use Zulu time instead of the local time?
When reading aviation literature, it's common to find references to Zulu Time.

What is Zulu Time?
Why does aviation use Zulu Time instead of the local time?

-1 for non-sufficient research effort

@kevin We can find everything on the Internet this days. I thought this question would be a nice add to this site.

If you're going to add a question to the site for completeness (and not because you personally want an answer), consider making it a full, detailed, complete good question.   The question you posted was barely two sentences, and not well formed.

Because local time can be complicated.

http://www.google.com/search?q=zulu+time

Why on earth would you use local time?!

@GabrielBrito If you want to add this kind of (rather trivial) question you should ensure it's of decent quality and searchable. Additionally you may want to answer your own question to avoid the kind of comments and downvotes you're getting. Odds are high that you'd then have people accusing you of farming reputation but that  behaviour is encouraged as long as both your question and answer are of good quality. If you don't care about the rep, post it as a community wiki.

Guys, please accept my apologize. I really did wanna know what is zulu time and why the aviation field uses it so much. When I'm reading ATCs transcriptions it's common to see they using it, and until now I hadn't fully understood the reason to not use the local time.
When I get home, I'll try to formulate a better question

@LightnessRacesinOrbit If you live near a timezone boundary, it's obvious why you'd want to use a standardized timezone and Zulu is the natural choice. If you don't (China, for example), it's not so obvious.

@DavidRicherby: Okay but it also seems obvious for there to be a global standard, on the realisation of which everything falls into place, no?

@LightnessRacesinOrbit Like all things, it's obvious to you if it's obvious.

Zulu means the letter Z in radio communication. The letter Z designates UTC time.
There is actually a list of time zones for each letter of the alphabet (except J):

Alpha time zone: UTC + 1
Bravo time zone: UTC + 2
...
India time zone: UTC + 9
Kilo time zone: UTC + 10
Lima time zone: UTC + 11
Mike time zone: UTC + 12
November time zone: UTC - 1
...
X-ray time zone: UTC - 11
Yankee time zone: UTC - 12
Zulu time zone: UTC + 0

However, the other time zones are seldom referenced in aviation.

Why do we use UTC time instead of local time?
Because flights often cross time zones.
Imagine this: the time now is 11:59. We will takeoff at 12:30 and fly west. Afterwards, at around 11:48, we will be 15 nautical miles away from the airport.....................Huh?
Even more confusing: We takeoff at 12:30 and land at 13:00 ==> we only need 30 minutes of fuel. Wrong! We actually cross a time zone and the actual flight time is 90 minutes. But we've taken off with 60 minutes less fuel than we need. What do we do?

To your last point: the flight from KIND to KORD takes 5 minutes if you're looking at your ticket - Depart IND 06:00, Arrive ORD 06:05. However, IND is on Eastern Time (UTC-5), while ORD is on Central Time (UTC-6)*. It's handy to get there in 5 minutes, but not realistic. *NOTE: UTC offsets are for Standard/Winter time, Daylight-Savings/Summer time the offsets are -4 & -5 -- another reason to use Zulu.

@FreeMan Those planes go really fast heading to Chicago, but they sure slow down making the reverse trip -- which probably takes like over 20 times as long, right? (5 minutes vs 120+) Maybe it'd be faster to fly to Chicago but just drive back???

@RalphJ, have you ever driven in Chicago traffic? There is nothing fast about leaving O'Hare by road.

Crossing the international date line going east, it's easy for one to land before one departs, based on local time.

Sometimes you don't need to cross the date line. Last week I flew from Helsinki to Stockholm, and arrived five minutes before I left.

I'd never noticed before that in Quebec the timezone is Quebec.  Interesting.

Zulu time, as others have pointed out, refers to UTC.  We use this time in aviation (and meteorology and surely others) because it is easier and it is standard.  It's the same time everywhere on earth.
If you are flying along the border between Arizona and New Mexico in the summer and given a hold:

Cessna 1234 hold at FIX, right turns, 10 mile legs, expect further clearance at 1630, time now 1602

If that were local time, you'd have to now determine if that fix is over AZ or NM, because NM observes daylight saving time and is in MDT/-0600 and AZ does not observe daylight saving time and is in MST/-0700.  This is a needless check that is distracting and can cause confusion all due to using a local time.  Instead, we know the times given are Z/UTC time and "1630" has an unambiguous meaning no matter where on earth our plane is located.
It is a similar situation when checking pre-flight weather.  Weather is reported in Z time and this makes it easy to calculate when you will get to your destination and what forecast is valid for that time.  If it were in local time you'd have to know additional information about time zones, which again could be a source of error and is needless.
Adding to potential confusion are regions of earth that keep odd adjustments.  For example, St. Johns, NL, Canada is GMT-0330 in the winter and GMT-0230 in the summer.  There are even a few that are off by 15 minute adjustments (e.g. Nepal).  Combine this with knowing where DST is observed and where it isn't, and more importantly when it is (USA DST has different start/end dates than other places) then it becomes very complicated to work in local time.  Working in universal time solves these problems.

And if you happen to be entering the hold around the start or end of daylight savings time, that would only add to the confusion!  While, it is again clear when given in Zulu time.

You mentioned AZ and NM but missed the punchline: the Navajo Nation, which is mostly in AZ but also extends into NM and Utah, does observe DST. And, if you miss your turn and head farther into the Navajo Nation, you come into the Hopi Indian Reservation which it surrounds, and which does not observe DST. And, if you were lined up right, you come to a tiny Navajo enclave-within-the-enclave, so you're back on DST again for a few miles. So, yeah, stick to Zulu.

"USA DST has different start/end dates than other places" That may be a little unfair, in that it suggests that the US is somehow out of step. DST is mostly a north-American and European thing. Historically, different countries changed on different dates but the European Union standardized the date for its members in 1996. Also, the US and Canada and some border areas of Mexico use the same date, so the claim doesn't hold in the most relevant cases; all it really means is "North America and Europe use different dates."

@DavidRicherby it is a bit US-centric, but North America isn't always in step.  The US shifted the DST start date in 2006 and Canada didn't switch until 2007 or 2008.  Mexico (parts of it anyway) uses different DST dates than either USA or Canada.

Zulu time is UTC time.
The reason for the name zulu is because there is a hour shift of Zero sometimes denoted with a Z and in the nato alphabet Z is Zulu.
Many times a route will cross timezone so to avoid confusion about which timezone a time is in controllers and pilots will use zulu time by default. It also avoids daylight savings issues.

Zulu time, used in aviation quite often, is another name for UTC (Coordinated Universal Time (French: temps universel coordonné)). It is the primary time standard by which the world regulates clocks and time. It is, within about 1 second, mean solar time at 0° longitude; it does not observe daylight saving time. It is one of several closely related successors to Greenwich Mean Time (GMT). For most purposes, UTC is considered interchangeable with GMT, but GMT is no longer precisely defined by the scientific community.
Edit
To answer the second part of your question : Its called Zulu time as UTC does not have daylight savings, hence Zero hour shift. Now Zero starts with Z and NATO call-sign for Z is Zulu. Hence the name.
Source

Neither GMT or UTC can have daylight saving time, because they are not time zones. They are time Sun-based references that don't adjust at all with economy (though GMT is no more a true reference). The funny thing is the time in Greenwich City is currently GMT+1 (more or less a few seconds).

@mins: Depends on what you call a “time-zone”, which is not clearly defined either. One normally calls “CET” a time-zone and it is not daylight-saving, the corresponding daylight-saving time being called “CEST”. On the other hand you can talk of time-zone for a city and it may or may not have daylight saving time depending on local rules.

@JanHudec: Agreed. I understand a country chooses its legal time based on a scientific reference (usually UTC) and offsets. Unix guys defined time zones as the set of such offsets. The corresponding file was never mature, consistent, or official. UTC and other time systems are references. The time zone database is now maintained by IETF. Zulu time is one of the military times.

Zulu time, sometimes called Greenwich Time or UTC time, is the local time at the Prime Meridian, that is on the 0° Line of Longitude, which also happens to run through Greenwich, England.  This local time has been adopted as International Standard Time and used as the official time on Earth.  Other local times are utilized by local principalities or nations as a relative standard time for that area of the Earth.  It is offset a certain number of hours from Zulu time.
As aircraft may be operating over several time zones during a cross country or international flight, it makes sense to file flight plans with departure and arrival times listed in Zulu time for easy reference.


text:
Do bluetooth aviation headsets and/or music negatively affect safety?
I'm in the process of getting my private pilot's license, and I've come to the point where it's probably time to think about buying a headset.
As I understand it there are a few options ranging from a standard mic and speakers, to passive noise cancellation, active noise cancellation, and even bluetooth for use with iPhones/MP3 players, which I think is awesome, however I'm concerned about distraction while flying.
Has listening to music and/or noise cancellation been at all shown to increase pilot error?
My main concerns are

What if I have a noise cancelling headset on, and the engine undergoes detonation, or what if the aircraft does something I should be alarmed about based on auditory cues that I can't hear?
Same situations as above, but even worse because I'm rocking out to some sweet tunes, is there the possibility that having music will exacerbate the aforementioned issues, or what if ATC comes on, and I hear them, but I don't register what they say because I was jamming to some Kenny Loggins?

Additionally, are commercial pilots permitted to use bluetooth headsets for phone calls? For music? Do crash statistics indicate that music and flying leads to more pilot-error? It certainly can't help...

I only have experience with Lightspeed Zulu's BT headset; there shouldn't be any concern with not registering what ATC says -- comm takes priority over BT and the headset will mute your BT while there's comm traffic to receive -- to the extent that you won't want to listen to music while you're on a frequency that has frequent traffic.

Related to in-flight music: Is it possible to “pimp up your aircraft” with an audio system?

To my knowledge there are no studies correlating ANR (or good quality passive) headsets with an increase in pilot error, but a several have been done on noise fatigue. There's even an old FAA advisory circular on the subject which basically boils down to "Multi-hour flights listening to the engines drone on and on will make the pilot cranky and error-prone"  - so from that perspective any good-quality headset is a safety enhancement.
As far as missing auditory cues because of ANR (things like the stall warning, funny engine noises, etc.) it's generally not a concern: ANR headsets are good, but they're not THAT good. Because of the way ANR works sudden sounds will cut through. You'll miss "long-term noise" (like the beat frequencies Falk mentioned from unsynchronized propellers), but you're not likely to miss anything safety-critical.
(One notable exception: ANR headsets are good at cutting out wind noise, so if you have a partially unlatched door you won't hear that.)
What you will notice with ANR headsets is that when the battery dies things get loud - sometimes louder than cheap passive headsets. Carrying extra batteries is a must with ANR headsets since having your noise reduction go away in the middle of a flight would be somewhat unpleasant.

As far as music, that's a mixed bag.  Much like having a CD playing in your car, I don't believe it's a significant safety impact unless you're being irresponsible with it (blasting it at a volume that drowns out everything around you, or rocking out when you should be watching for traffic).
Additionally, all the intercoms and headsets I've seen give the com radio priority, and will either cut out or substantially mute the music input when there's radio traffic.  This makes you less likely to miss radio calls, but it also makes listening to music in the plane an absolutely DREADFUL experience (in the northeast where I am there's always somebody talking on the frequency - if you hear half of the song between the radio cutting in it's a good day).
I personally find the distraction from the music muting/unmuting to be more of an issue than boredom from not having music in the first place (if you're that bored you can always look out the window, or tune a local CTAF frequency and listen to the antics), but your experience may vary substantially if you're in an area where the radio is quieter.

Policies for commercial pilots would vary depending on the operation, but for airline pilots using your personal cell phone is forbidden, and before it was forbidden by the FAA it was usually prohibited by the airline.
Part 91 operations (a ferry flight, or a crop duster spraying the local fields) wouldn't be subject to that restriction though, and making a phone call or listening to music would be permissible under the FARs. With all the studies on the negative safety effects of using a cell phone while driving I wouldn't recommend the phone call, but I imagine crop dusting is more fun if you have some music to listen to…

@bwheeler96 As a personal note, I'm not a fan of ANR (I already have batteries in my flashlight, my handheld radio, and my pulse oximeter that I have to remember to check - what do I want them in my headset for?!) - I'm wearing one of these and I quite like it.

There are headsets which offer you to choose if they should turn the musics volume down with an incoming transmission or simply do nothing. If you have a good setup of the intercom, the radio and the music volume then it's quite nice to have music, even on some more saturated enroute frequencies.

@Falk my audio panel has the same option (and I'll admit I occasionally do turn off the mute function if I'm flying somewhere without much activity and I can mostly-ignore the radio) but I'm not really comfortable turing off the mute function if I'm actually talking to ATC, or if I'm listening to the frequency in busy airspace for situational awareness. I'd hate to be "That Guy" on the frequency who misses calls or constantly comes back to the controller with "Say again" or "Was that for me?"

That's the point where I either turn off the music, or turn the volume down - you still have it then and it's not intermittent. But I this is really dependent on personal preference and also the kind of music you are listening to: think about some sort of metal as background noise - no way.

There are also ANR headsets with no batteries that are powered by the audio jack.  Much better with no batteries!

Let me share some of my experiences with my active noise cancelling headset when flying piston aeroplanes. First, if you fly multi-engine and the props are not synchronizing automatically everyone without active noise cancelling on board will definitely hate you - you really don't hear that horrible sound which is really comfortable especially while practicing engine failures. Beside of this you are still able to hear everything whats going on. It there are abrupt noises or warning horns you'll be able to hear them. Active noise cancelling can really help you to be concentrated and allows you to hear ATC much clearer than before. This is especially valuable on crowded frequencies or while getting an ATIS, but also being under radar control/services.
Listening to music while flying is a different story. It can be distracting and I'm still cautious using this great feature. On long x- countries it's really amazing to have it while I would for sure turn it off approaching a busy airport. It can definitely influence your ability to focus on the flight, but sometimes I think even on a positive way keeping you in a good mood.
The best you can do is to try it, because everyone is different. Find the best settings for your self and make your own experiences. There are aviation shops which will give you a headset to try it, otherwise you can ask friends who may have one, or order via the internet and if you don't really feel comfortable with the one you ordered you can return it during a specified period of time.
One last and really important point: If you tested it and decided to spend some extra money on a high-end headset look for special offers. There are a bunch of websites where you can safe a lot of money. I would always check if you still have the original guarantee.

Thanks for the great answer! I can see that noise cancellation is pretty much a must if I want to fly larger aircraft

I don't think that it is a 'must have' and the aircrafts size doesn't make a difference, too. It's all about your personal preference. I knew a lot of people who love their passive headset. Price, weight, form, material and of cause sound are important points and everyone has different ears, which are more or less sensitive and all have a different form. Try, try, try and don't forget to wear you sunglasses, or if you have glasses while trying.


text:
Why would an airport have a beacon light on when there's no traffic?
I live in a small town (Lone Pine, CA) with a tiny airport that sees a couple planes a week at best... busy-ish days when a major fire is happening. Over the past month the airport beacon light has been running all night long, never stops and I have seen one plane land. This never happened in the past. This just started. The lights shines in my window all night and I am trying to understand the reasoning behind it.
I get airports need to have it on when planes are approaching but the question is why all night with no air traffic? Some say its broken and its supposed to be triggered by oncoming aircraft while other says its FAA regulation to have it on dawn till dusk.

Welcome to Aviation.SE! I edited your question to a format that is generally better received at this website. Feel free to roll back if you disagree.

I know from posts here, that incoming planes can switch ON lights via radio themselves, but you say it is always ON and only a beacon, not the runway itself?

For what it's worth, the FAA says an average of 24 aircraft movements (i.e. takeoff or landing) happened at that field per day for the 12-month period from June 2016 to June 2017.

It's an untowered airport. Who would turn on the light when an aircraft approaches? Not all aircraft have a transponder or radio.

The Chart Supplement says "Arpt bcn OTS indef."
("Airport Beacon is Out of Service, indefinitely")
It also says "ACTIVATE MIRL Rwy 16–34 and bcn—CTAF"
("Activate the Medium Intensity Runway Lights(MIRL) for Runway 16/34 and the Becaon, by using the CTAF")
Based on this, it is unclear if the beacon is out of service, or pilot-activated.
But it is clear that it should not be on all night.
A phone number is listed on that page for the airport manager, and I might start there.
After that, consider contacting the local Flight Standards District Office (FSDO).

you rule!!! thank you!

Please report back on what the various sources say.  I'm interested to see how this is resolved.

The beacon light is on because it can be seen from a considerable distance, and so is used not just by planes landing at that airport (really, it's pretty useless for landing).  It's used by planes passing through.  For instance, if I were to fly from around Reno to the LA Basin at night, I'd probably see the Lone Pine beacon not long after passing the Mammoth airport.  Not only does it show me the way, being able to see it proves that there are no mountain &c between me and it, which is rather a comfort on a dark night :-)
The beacon really should be shielded so that it's not visible/annoying from ground level.  Have you talked to the airport staff?


text:
What is the difference between GVI and DVI?
In any maintenance program I found some terms like General Visual Inspection (GVI) or Detail Visual Inspection (DVI) or Detailed Inspection (DTI). I want to know the difference between these types of inspection.
And which type of inspection is required in which cases.

Is that linked to EASA means of compliance? Related: Clarification  of  Definitions  for  General  Visual  (GVI),  Detailed  (DET),  and Special Detailed (SDI) Inspections

Terms like these, when used in a manual, are usually defined within the manual itself.

GVI is general visual inspection and when you make a GVI, you have to be maximum an arm's length distance to the area and/or component you are searching any defects.
DVI is detailed visual inspection, it depends to the situation but usually you use a tool like a magnifier to inspect the area/component.

GVI and DVI can be differentiated by the distance of visual.
GVI is further back and overview of the whole area, doesn't fall under any zonal inspection.
While DVI is closer visual inspection, can be enhanced by using magnifying glass.
There is SDI special detail inspection, this inspection is to find hidden faults using non destructive testing (tap test/rotor test/dye penetrant/...)
When there is a finding on GVI, further DVI can be carried out. This follows the card that had been issued.

"This follows the card that had been issued." What is a card? Is this specific to a particular carrier's operations (if so you should specify that), or is this a general purpose term that's applicable to all inspections. Please [edit] your answer to include some further details.


text:
What are the differences between single and double annular combustion chambers?
The combustion chamber of a jet engine may be can type or annular type. Annular type combustion chamber can be SAC (single annular combustion chamber) or DAC (double annular combustion chamber). What are the major changes between these  two types of combustion chamber? Is the CFM56-7B26 a SAC or DAC engine?

See this answer for the difference between a SAC and DAC combustor. The EASA type certificate for the CFM56-7 also identifies which engines have the DAC and which have the SAC. The answer depends on exactly which -7B26 version you are referring to.


text:
What type of coordinate system is this?
In case you want to say spherical coordinate system: no it is not a spherical coordinate system.
I found this image in a book about flight management systems where they explain the different types of coordinate systems it can use.
The ukrainian name for it is: "ортодромічної" coordinate system
What is the English name of this coordinate system and what advantages may it offer over another (eg spherical coordinate system)?

"ортодромічної" seems to translate to "orthodromic", i.e. "great-circle based" (https://en.wikipedia.org/wiki/Great-circle_distance). 2. What is P0? the destination? 3. the fact that it is not using the poles does not mean it is not a spherical coordinate system, just rotate it and it will match a "standard" spherical coordinate system 4. "standard" because any system that has 2 angles and 1 radius (in this case this is fixed) is a s.c.s.

I can't read Cyrillic, so this does not help me much :|. To answer your comment, I don't know, it might be convenient for the programmer given the requirements, or it might be a convention used in Ukraine/ex soviet countries.

no, but I am not an expert in the field. IMO, you might have better luck on GIS.SE, but you have ask a mod to move your question there.

The document is about navigation.
By using an online OCR tool (I used this one which is not so good) on page 177 of the document, and then translating from Ukrainian using Google Translate:

... I can confirm @Federico 's suggestion: This figure doesn't introduce a new coordinate system, it just tells about rotating a good ol' geographic coordinate system to facilitate navigation / calculation.
A GCS is defined by its equator, rotating it means the equator is not anymore the Earth equator.
Such frame transformation is also used for INS (SINS) to minimize the accumulation of rounding errors. Just changing the frame orientation allows a better use of the same sensors.

This document says, with fig 7.7, that in some cases, depending on the type of mission or route of the aircraft, it is appropriate to rotate the usual GCS (latitude, longitude) to facilitate calculations and increase accuracy of the results.
An example is, when following a great circle (orthodromy), to align latitude and longitude so that the system equator is parallel to the great circle to follow.
You will easily improve both the OCR rendering and the translation by spending some time on it.

I made this answer a community wiki, so anyone can improve it.

I don't really speak Ukrainian but I disagree with @Federico. In p.176, first phrase after the title, the 'orthodromic' coordinate system (CK- funnily translated as UK) in question is listed with the geodesic, normal spherical and many others as a standalone coordinate system. According to a random user I just found in an airplane navigation forum Russian navigation has a large orthodrome-related terminology ("Russians made love on orthodromes"). I couldn't find the English equivalent.

P0 is probably the flight destination. The coordinate system is spherical and x,y can be given as an angle or distance.

What do you mean by "geodetic CS of an aircraft"? A geodetic frame of reference would be EFEC, not moving with and centered on the aircraft as does a body CS.

(sorry for replying late) I mean a CS centered around the CG with z pointing in the same direction as the gravity vector, x usually points north. The correct name (which I didn't know until now) is "aircraft carried normal earth axis system".


text:
How does the attitude and heading reference (AHRS) work on Boeing 737 aircraft?
I would like to know how the AHRS work on Boeing 737 aircraft. If this aircraft (like every the other ones I guess) has an Inertial Reference System (IRS), composed of 3 accelerometers and 3 gyroscopes, what elements compose its AHRS?
3 accelerometers and 3 gyroscopes as well?

The 737 does not have a separate AHRS. Those functions are simply outputs from the two IRS's.
(Source) 737 IRS panel.
ATT (attitude) mode selects the AHRS-only output of the IRS.

Thank you for this info! What I am actually trying to figure out is Boeing's flight management system's "architecture" i.e.: does it use GPS, does it use radio navigation, does it use AHRS, automatic compass, etc... Any idea about how I can find that out?

@traducerad  For a good description, check out this document from SmartCockpit.com.  Flight Management and Navigation  It's a bit long to try and summarize here.


text:
How will radar systems be used in FAA's NextGen ATC plans?
Based on the reading I've been doing of FAA's Next Generation Air Traffic Control (NextGen) plans, I've been wondering if and how radar systems will continue to be used for ATC as NextGen rolls out?
Questions include:

Is it correct to assert that radar coverage will effectively become a less precise, backup only, data feed? I am suggesting this because my understanding (which could easily be incorrect) is that ADS-B will mandated for most (everyone?) and so aircraft will be actively reporting their precise position without the need for a radar track.
Will existing radar coverage eventually be phased out?  Seems unlikely due to airspace security issues alone. But are there any other reasons to keep radar coverage?

Under the ADS-B rule of the FAA aircraft operating in Classes A, B, and C airspace, as well as certain other specified classes of airspace
within the U.S. National Airspace System are required to operate ADS-B Out avionics.
This means that these aircraft can be tracked without the use of radar. These ADS-B tracks will be more accurate than radar tracks and have a higher update rate. However for reasons of integrity, continuity of service and security, radar will continue to provide coverage. Currently a lot of airspace is covered by multiple radar layers, the introduction of ADS-B allows for a reduction in redundant radar coverage.
Aircraft not equipped with ADS-B (operating outside of class A,B, or C airspace) will be tracked using radar. The radar tracks will be broadcast on TIS-B (Traffic Information Service - Broadcast) so that aircraft with ADS-B In receivers detect these aircraft as well.

Also, once the ADS-B mandate takes effect in 2020, the FAA will gradually allow SSR (Secondary Surveillance Radar) coverage redundancy to be reduced as equipment fails, rather than repairing it.  Currently, they have heavily overlapping radar to provide failure resistance.  I think I've heard that the FAA operates more than triple-redundant SSR coverage.  The FAA supposedly could safely shut down approximately half of their SSR stations and still meet their backup needs.*


text:
What are the Ikarus C42 wing loading limits?
I have been reading about the Ikarus C42 aircraft as a potential personal recreation aircraft.  It compares very favorably with the Cessna 152, most notably in weight, stall speed, and fuel economy.
Does anyone have info on the negative and positive G loading limits for this aircraft? Can it be dis-assembled for transportation and storage? Thanks.

Yes, I am interested in this "Volks Flugzeug".  Need to know how strong it is.  Not that I am planning aerobatics, like its lower landing speed.  Also curious about a bipe version.  Thanks!.

My club has a C42B that is used both as a trainer and a recreational aircraft, so I stopped by and looked in the Pilot's Operating Handbook for that one.
Now, before I say anything else: obviously, if the exact values matter, then always consult the POH for the specific airframe in question!
With the above preliminaries thus out of the way:

The structural limits are stated as maximum positive wing loading +4 G, and maximum negative wing loading -2 G.
The wings can be removed, and the POH lays out the procedure for this (as well as, obviously, that for reattaching them).

At least while quickly glancing through the text, I didn't spot anything obvious which would indicate that this differs between variants in the C42 series.

Thanks, appreciate the info.

@RobertDiGiovanni I notice you haven't upvoted or accepted. Are you looking for more in an answer?

No, looks very strong.  Thanks.


text:
Can I legally taxi a seaplane in a canal or channel?
I live on a good sized canal in a subdivision in Florida, USA.

Is it legal for me to taxi down the canal about 100 yards?
Is it legal for me to taxi down a large main channel which is part of the Gulf of Mexico to take off?

Also, when meeting a boat, who has right of way: the boat or the seaplane?

Are you asking if this is physically possible or legally permitted?

Closely related, but more specific : http://aviation.stackexchange.com/q/177/69

Ask Seaplane pilots assn. they have s book the goes through all the rules in 50 states and lists  seaplane-friendly waters

Is it legally permitted? who has right of way in channel boats or sea plane? I assume the plane is treated as a  boat.

Bump - this is a good question. I would suspect it centers on who owns the waterway and if it's private if they have given you permission.

I would advise checking out the FAA's seaplane handbook for more information. In general local ordinances tend to be the issue here and not the FAA's regulations.
You can find the right of way rules in 14 CFR 91.115

§ 91.115 Right-of-way rules: Water operations.
(a) General. Each
  person operating an aircraft on the water shall, insofar as possible,
  keep clear of all vessels and avoid impeding their navigation, and
  shall give way to any vessel or other aircraft that is given the
  right-of-way by any rule of this section.
(b) Crossing. When aircraft, or an aircraft and a vessel, are on
  crossing courses, the aircraft or vessel to the other's right has the
  right-of-way.
(c) Approaching head-on. When aircraft, or an aircraft and a vessel,
  are approaching head-on, or nearly so, each shall alter its course to
  the right to keep well clear.
(d) Overtaking. Each aircraft or vessel that is being overtaken has
  the right-of-way, and the one overtaking shall alter course to keep
  well clear.
(e) Special circumstances. When aircraft, or an aircraft and a vessel,
  approach so as to involve risk of collision, each aircraft or vessel
  shall proceed with careful regard to existing circumstances, including
  the limitations of the respective craft.

There is also a note from the hand book,

Pilots are encouraged to obtain the USCG Navigation Rules,
  International-Inland, M16672.2D, available from the U.S. Government
  Printing Office. These rules apply to all public or private vessels
  navigating upon the high seas and certain inland waters.

Although you should not expect your average boater to understand or even be aware of the FAA regulations on this. As such caution should always be used. Keep in mind that in most if not all states you don't even need a license to operate most personal sized boats (under 65 ft. generally).
You will need to check with your local municipality (who ultimately has jurisdiction over the water way most likely). Unfortunately they may have local ordinances that are more intended for land based aircraft but may incidentally apply to you. Things like noise abatement may also stand in your way, keep in mind a plane is significantly louder than most boats.
This FAQ covers a lot of really good questions about where you can and can't land and other seaplane related topics.
Of interest to you may be Question 2

2. Where can I keep my seaplane?
A seaplane can be kept at a certified seaplane base with permission, or at an  airport if it is equipped with
  amphibious floats. If you want to keep your seaplane "off airport",
  however, you will need to explore the issue with your state
  aeronautics office, local government and the owner of the waterway.
  Some specific problems include mooring restrictions imposed by the US
  Army Corps of Engineers, seaplane base licensing requirements imposed
  by state governments and zoning regulations imposed by local
  jurisdictions.

In this kind of situation I would personally seek out a local lawyer that specializes in aviation related matters (a call to your local GA field may get you a name). Unfortunately many local authorities don't always understand the regulations and many don't even know its with in their power to regulate such operations since the cases tend to be few and far between. In other cases older forgotten regulations may have relegated them selves to a dusty file cabinet that no one remembers. Other local sea plane owners may also be of help here.
It is also worth considering if you have the width to actually pull this off. Even the biggest boats I have been on (in and around the 55ft. size) are generally no wider than around 15ft. at the widest point. A Cessna 172 has a 36ft. wingspan which is something worth thinking about.

It sounds like section 91.115 is saying, "If you float, you're a boat".

@user19474, it looks more like "if you float, you're a boat, but the real boats have right-of-way".

@Mark The rules above seem to apply to boats and planes equally. The only one that doesn't is section a, which seems to be saying "Stay out of shipping lanes, if you can".

Yes, you can, unless limited by local law, unless you're taxiing on private property which is unlikely if part of the Inter Coastal waterway However there's so many little rules and laws locally, you may want to further check with the Sea Plane Assn.


text:
Do safety-critical avionics systems run Linux?
I have heard diverse things about this. Some people claim that running Linux on safety-critical avionics systems is a very bad idea. On the other hand some people (who are rather unfamiliar with avionics) said this is not true.
So I would like to know, do aircraft nowadays run on a Linux distribution?
Is it a good idea to incorporate Linux in aircraft? If not, why?

Related

Safety critical avionics are usually single purpose. They probably don't even run an OS in the normal sense.

You wouldn't want your avionics system to run on any operating system that's liable to say, "Hey, you know what, I think I'll run this other process for a while."

Ex-avionics engineer.  The only place you will find off-the-shelf operating systems is in some in-flight-entertainment systems (e.g. some use Android or Windows CE).  Even then, most of the big suppliers use their own custom platforms.  The safety critical stuff only runs on proprietary, single purpose OSes.  Linux, Windows and so on are not designed for purpose and just too buggy for avionics use.  The people saying it's a bad idea are not pretending, it's true.

@Simon how can one prove that Linux is too buggy and not the best option?

you don't prove that is too buggy, you assume everything is buggy, and if you really really want to use something, you prove it is NOT buggy.

@traducerad Certifying a Linux kernel for use in avionics would be an incredibly complex task that would cost more than simply using an RTOS that is specifically designed, documented, and tested with DO-178 in mind.

Kinda related: some of the Nasa rovers they send on Mars use a proprietary RTOS (Real Time OS): VxWorks. But I can't say it could be used for avionics.

@kebs: It can, and is. VxWorks is DO-178 certified and used by both Boeing and Airbus.

@MSalters: How in the world does VxWorks manage real-time on x86? (Apparently it supports x86?!)

Doesn't take much to prove Linux is too buggy. My wife crashed one of the games on an in-flight entertainment system, and we watched a penguin scroll past as the thing rebooted.

None of the avionics systems I've worked on have used Linux or any consumer-type operating system. There are a few main issues.
First is the practical. Most safety-critical avionics involve a control loop and thus have a real-time requirement. That means it's not just important to run a process and get an answer, you need to get the answer within a tightly-controlled time constraint.  Every critical software process on an aircraft is scheduled to ensure that you have a stable control loop.  To do that, you need a real-time OS and Linux isn't one.
Second is the need for certification.  Software used on an aircraft has to be developed to meet the appropriate development assurance level (DAL) for the associated hazard level.  Safety critical systems are required to meet DAL level "A". Any OS you use has to meet the same DAL as the function running on it.  These requirements are defined in RTCA DO-178C. Linux wasn't developed to this standard. There are only a few OS/software development platforms that are capable of being certified. Green Hills, Wind River, and LynxOS are the few systems I'm familiar with that meet the requirements.
There is also one other constraint in that certification requires very stringent version control.  Avionics will exist in the field for many years and any changes to it have to be certified as well.  Generally, there's no valid reason to update the OS on an old unit, and in many cases you couldn't without upgrading hardware (which is a bigger expense no one wants). So in updating an old unit I have to build the 'new' software to run on the whatever version of OS currently exists in the product. That could be a 15 or 20 years old (or older) platform. A rapidly evolving OS such as Linux would have a negative impact on long term product support.

This might be stupid but... Linux has a real-time patch. What do you think  about that? Would that make your first point invalid?

@traducerad, As far as I know, the RTLinux patch/project is aimed at a different target, like audio processing or some high performance computing: you don't get a truly real-time operating system (like Integrity, for instance).

The reason Linux wouldn't be used is because of the certification burden placed on any software running safety critical functions on a type certified aircraft.
Now not all software has to meet DAL A, the software has to meet the highest criticality level for the function that it performs.

Also, Linux would be brutal overkill for that kind of systems. Each component only runs a rather narrowly defined function, so the operating system can be much simpler (which makes it easier to certify too).

On the other hand, Linux might be running on some other systems in the aircraft. It is used in some flight entertainment systems and could possibly be used in the integrated “electronic flight bag”—though I don't know whether it actually is.

Related: The Linux Scheduler: a Decade of Wasted Cores and Linux scheduler latency (for single core).

@JanHudec  Linux could be used in an Class 1 or Class 2 EFB but it's more likely that it would be an iPad or laptop running Windows or MacOS. It's about cost and you just don't see many Linux laptops around (Don't forget crew training.) I am not aware of any airlines using Class 3 EFBs as they are installed equipment and subject to certification requirements. Why add all that expense and headache when a tablet or laptop can be used?

@Gerry, I do see many Linux tablets though (because Android is Linux — just not a GNU/Linux).

@Gerry, airlines would not install Class 3 EFB in aircraft that don't come with one from manufacturer, but AFAICT A380, A350 and B787 do.

You say "Wind River, and LynxOS" but from my understanding Wind River is a supplier that makes LynxOS.  They aren't two separate operating systems.

Wind River makes VxWorks.

@MarcoSanfilippo what do you mean by "true real time ... (like Integtrity) "? Real time is real time, there is no way around that

@traducerad I meant something like hard real time vs soft real time. If a system is performing, for instance, a real time audio processing task it can safely skip a few samples. If a system is managing the hydraulic actuators of a stabilyzer it can't skip a few input commands. :-)

The short answer is that no safety-critical avionics systems that I'm aware of use Linux, and the highest criticality systems often don't use a commercial operating system at all. However, Linux is used in other safety-critical applicaitons like the Space X Falcon 9 and medical applications.  A more detailed explanation is difficult to do without going into too much depth, since the question is kind of like asking "are modern airframes made with nanomaterials?", where a detailed explanation would have to cover the pros and cons of the material, places where its use makes the most and least sense, differences in manufacturers, and an overview of what's used instead, etc.  I'll try to cover all those points succinctly with links to further information.
According to this FAA report from 2001, some of the major operating systems for certified avionics were VRTX, LynxOS, PSOS, VxWorks, and Enea's OSE, although non-critical avionics sometimes use other systems like Windows NT.  (Yes, LynxOS is based on Unix and Linux is considered "Unix-like", but there are many differences between the two, just like how a Linux isn't similar to the BSD-based Mac OS X). However, the most critical systems don't use a commercial OS at all.  They note  "With the evidence available today, in general, it can be stated that COTS products typically do not meet the requirements for level A criticality software."  In layman's terms, that means most avionics developed with third-party software, from VxWorks to Linux, weren't being tested and analyzed enough to be put in something critical like a landing system, TCAS unit, or critical display unit.  That's likely changed in the 10+ years since the report was written, however.  Here's a more recent article on real-time operating system usage in avionics.
What do RTOS and COTS mean?
An important concept here is a real-time operating system, or RTOS.  A RTOS in a nutshell provides guarantees that software won't run out of scheduled computing time, messages between parts of the software are passed in a small amount of time, memory won't run out, and other important tasks are guaranteed instead of working well under normal conditions then breaking under unusual conditions.  Normal operating systems can't make such guarantees.  These guarantees, or acceptable substitutes, are required for certification of most avionics.
Another important concept is the difference between in-house and commerical off-the-shelf (COTS) systems.  Commercial off-the-shelf systems are publicly available and are not customized much for each manufacturer.    This article  provides a good summary of pro's and cons of commercial and in-house operating systems.  Many high-criticality avionics still have the core software developed in-house due to the advantages involved.
Does Linux meet certification requirements?
Yes, Linux is not "FAA certified" but actually no RTOS is "FAA certified" or "meets DO-178C". DO-178C provides objectives that the avionics system engineers have to fulfill in order to certify their whole avionics software (the objectives cover audits, testing, safety analysis, and requirement writing, among other things).  So the best the OS supplier can do is provide "DO-178C ready" software or follow DO-178C guidelines. Note that DO-178C recognizes various safety levels, so what's certifiable under DO-178C for a maintenance system may not be certifiable under DO-178C for a critical display unit.  The problem with Linux isn't that Linux isn't "certified under DO-178C", it's that it's difficult to certify due to challenges noted below.  It's possible to certify a system using Linux, but doing so could be prohibitively difficult due to the extra analysis, safety measures, and documentation that would be needed, especially for the most critical avionics.  Some of these challenges and alternate methods of compliance are outlined in this FAA report.
Advantages and disadvantages of Linux
There are advantages to using Linux, which are partly shared with other commercial systems.  More employees will already have expertise with Linux, and the OS was designed with more expertise and time than most organizations have available.  Commercial systems also have a much lower sticker price than in-house software.  Commercial systems are also more adaptable and allow changes to hardware and room for future growth without going back to the drawing board.  Tooling to work with the software is more developed, and they may also have a longer service history that provides confidence in the software.
Here are some of the issues Linux faces in an avionics system when competing with a RTOS, from this FAA report:

partitioning: If two programs are supposed to be running independently, there needs to be evidence that one program can't interfere with another through shared memory structure, caches, board support and firmware, errors, interrupts, etc.

worst case execution time:  In desktop computing it's ok if I bog down my PC with too many requests or unusual conditions at once and the system slows down or skips some program steps.  In avionics this is not acceptable for obvious reasons.  The supplier would need to verify this either through models of the CPU, memory, etc. or rigorous lab tests and timing analysis.  Both are more difficult the more complex your hardware and software is.

MCDC coverage:  Tests on the most critical avionics (Level A) requires running enough lines of code and decision conditions to reach the MCDC code coverage standard, which falls between "run every line of code" and exhaustive tests of every combination of conditions.   Some operating systems like Linux can be extremely difficult to test thoroughly enough to meet this standard.

documentation:  Rigorous analysis and stress test requires a lot of documentation on inner workings of the OS

security considerations: Because of its large size, Linux has more security problems than a lean, in-house application. These security issues are becoming
increasingly important, especially in the military

dead and unreachable code:  Carefully disabling the many unused functions of Linux and guaranteeing
they can't interfere in your software is usually required for
certification

Other safety-critical industries
What about similar safety-critical industries?  The Space X Falcon does use Linux in some of its flight computers (sources).  Based on this interview, Space X seems to prioritize future growth, availability, short cycle times, and expertise over the simplicity and robustness of in-house development in this area. Note that the flight control computers on the Space X Falcon aren't directly analogous to an LRU in typical modern avionics, so extra work or an unusual architecture would likely be required to get Linux to work for typical avionics applications.
Linux is also used in many safety-critical medical applications, but not without problems similar to those faced in aviation.  I'd recommend reading Wind River's "Choosing Linux for Medical Devices", or this article on the disadvantages of Linux in safety-critical medical applications.
I'm assuming you're talking about the principal avionics like flight guidance, autopilot, fly-by-wire, or displays.  Other airplane systems could loosely be considered to be safety-critical but aren't typical examples of safety-critical devices, like certified electronic flight bags, connectivity solutions, and maintenance software.  These are sometimes better suited for a Linux application due to high complexity and less rigorous safety considerations.
Note that I'm not an expert in this field and my advice does not replace the advice of a certification specialist.

Very good and thorough answer. I'd also point out that a majority of avionics dont use an RTOS at all, preferring to execute on the processor directly.

I have to take issue with your statement that "LynxOS is based on Unix, just like Linux". Linux is "based on Unix" in much the same way that Windows 8 is "based on CP/M", in that they do share a little common history, but are completely separate implementations. (That Unix systems proper have taken on some of the userland software typically seen on Linux systems, particularly GNU, is another matter.) It would be better to say that Linux implements the POSIX standard, to which most Unixes (I don't know about LynxOS) also conform; that doesn't, however, make Linux "based on Unix".

@MichaelKjörling I clarified that Linux is "Unix like" and that there are many differences between the two. My main point here is to clarify that LynxOS is not just another flavor of Linux.  I don't think we should get into the nuances like how Linux distros is only mostly POSIX-compliant and uncertified for POSIX.

To clarify some misconceptions about Linux which run across many of the answers given.
Linux is NOT a "commercial" OS. It is free for anybody to download and hack about as they please. (Some companies package it up with a load of apps as a distribution or "distro" and do charge for supporting the package).
Linux is NOT a monolithic build with loads of extraneous functions. The Linux kernel core is lean and mean enough to be installed on smartwatches and many other embedded devices. The frills are supplied by a multitude of optional kernel modules. When you build your Linux kernel for installation, you choose which modules you want, and whether you want them rolled into a single blob with the core (fast) or hung around it as separate blobs (operationally flexible).
Linux is NOT a "userland" OS. For that you have to add an interface layer such as GNU or Android. It is used extensively in embedded applications, where the company engineers have done the stuff described above.
Linux is no more insecure than any other OS. Indeed, many regard it as among the most secure. It is the userland bit where distros like Android go horribly wrong, while another rash of recent exploits focused on hardware design flaws.
Linux can be as stable and supportable as you want it to be. An avionics OS company can happily support a given kernel build for twenty years and more, and simply ignore the relentless stream of advances unless and until they need to tap it for an upgrade or a new product. A given tweak may often be "backported" to your old build so you don't need to deal with the full upgrade.
Linux has various real-time tweaks available if you want to use them. Possibly none are fully satisfactory for core flight control, but the open licensing means there is nothing in principle to stop you rolling up your sleeves and tweaking it yourself. You can then feed your code back into the Linux source tree and others may then use and further improve it.
Having said all that, it is a lot of work to customise Linux for your given hardware/software regime and the open licensing makes it difficult to charge heavy royalties. Specialist software houses therefore find it equally difficult to build a living off that, so unless an avionics house wants the expense of customising its own OS, it will find only commercially licensed offerings available from the specialists.
This last is the main reason why Linux seldom if ever appears in avionics, and why all the other issues don't get addressed.
On the other hand, if you include consumer and low-end commercial drones, Linux is already popular if not dominant. There is no doubt that over the coming years it will be working its way steadily up the food chain.

Seems that pilots now at least sometimes use tablets for checklists.
If these tablets are Android devices (majority of them), then they run Linux kernel. Android uses less of standard Linux stack but it still uses Linux kernel. Checklists are safety critical, I think. Apple and Windows tablets use different kernels, not Linux.
There are many checklist apps for Android devices. I assume somebody uses them.
Kernel is the core of a computer's operating system that keeps complete control over all other parts. Like wiring for an airliner.

As well as the mapping programs.

Checklists are important, but they aren't safety critical in the same way that, say, a FBW system is, so they wouldn't be subject to the same development assurance level for safety critical equipment as other avionics.

Is Linux used for safety critical applications? No. Yes. Perhaps. Bear with me...

The USS Zumwalt uses Linux for its extensive data requirements, and LynxOS for embedded hard real-time applications, described in this article.
Standard laptop Linux is a user space Operating System: it waits until a user clicks a mouse, hits a key, or generates an output, and then takes action. There may or may not be many programs open. User input is a statistical event as far as the O/S is concerned: it may or may not happen in the next minute.
Contrast that with a digital control loop. It runs on a processor and uses memory, just standard computer hardware. But they differ from desktop software in that they:

Are embedded;
Have a set of pre-defined tasks;
Have strict timing constraints;
Run in an endless loop. At the end of the program it jumps back to the start and goes through the routine again, this would be one iteration frame.

The software needs to read inputs and generate outputs, every iteration, and an iteration frame runs for a fixed amount of time. A hard real time system is a system where timed responses must be deterministic: whatever it does must be finished within one software iteration. If the control loop runs at 100 Hz, an iteration cycle takes 10 msec, and the hardware needs to be fast enough to guarantee that the whole process can finish within time, every time.
These control loops are generally not huge, and generally don't have a number of windows open between 1 and 100. Small and fast programs and a limited number of windows, that is how O/Ses for safety critical programs and real-time loops are made for. Which is great, in the olden days there did not use to be an O/S for this and code had to be written in assembler or worse. I/O calls were hardware specific and therefore not portable from one chipset to another.
This is where the real-time O/Ses such as VxWorks, LynxOS and a few others come in. They are Unix based, POSIX compatible O/Ses. The hardware layer is made invisible for the programmer, who has a set of development tools for using high level computer languages with standard I/O calls and timing routines. They are scalable: you can start with an O/S that just boots and then immediately runs your cross-compiled binary at a rate set at the timer interface. Or you can re-configure the kernel and include a couple of user interrupts that look at keyboards or RS-232 data coming in, all up to the programmer, who also has an extensive tool kit for timing and I/O.
VxWorks can be expensive (but is well supported), and there are now some open source alternatives available based on the linux kernel such as Xenomai, RTLinux, and Xilinx. Some of these attempt to have all services available for desktop applications and only have an interrupt timer that does its best to keep the task running evenly, even if a word processor starts a spelling check. Others are scalable hard time, just like VxWorks, but are open source and support may be a challenge. As far as I know they have not been to Mars yet, VxWorks has.
Can it be used for safety critical avionics: yes, if scalable hard real time, and tested according to the standards applicable for all avionics. As far as I now there is nothing yet on board of aircraft, but that may just be a matter of time.

"The hardware needs to be fast enough to guarantee that the process can finish within one cycle." I think you are mixing up clock cycles and time slices. Single instructions, such as fetches and jumps may take multiple clock cycles to complete, just a context switch in and out of an interrupt is more than one clock cycle. A "process" cannot physically complete in a single clock cycle.

Yes, if we aim for technical correctness, @RonBeyer is correct. While you're editing, you may also want to change "user space operating system" to "user-oriented operating system". In low-level software development, such as that you'd be involved in if you're working on an operating system, "userspace" typically means unprivileged code executing under the supervision of the operating system; the opposite is often referred to as "kernel space" which, as you may have guessed, is how the OS kernel executes, without supervision. Note that this is different from admin/regular user account privs.

@RonBeyer Indeed, not the processor clock of course.

@MichaelKjörling There is no unprivileged code in a hard real-time O/S.

That is NOT the "USS Umwalt", it is the "USS ZUMWALT"; note the spelling of my last name. And yes I am related to the now deceased Admiral Elmo Zumwalt which this ship and class of ships is named after.

none of the arguments exchanged in here is completely wrong, but i would wish some participants would apply a little more effort in balancing their arguments.
The real buzz-words for aviation are real time and safety.
Of cause, in aviation safety comes first and if you need something to happen, most of the time it has to happen immediately and something has to prove to the pilot that the job is done.
Before you can certify something, you have to verify and validate it - that can be a pain in the neck. And thats why most people dont like that.
Linux is not too complex to be tested and used in aviation - but the desktop flavour is.
Linux in its software-design is quite well suited for use in aviation, like  most Posix  conforming software. Linux's beauty is that every component is designed to do exactly one job and this to its best (in contrast to Windows). For aviation you would never use a complex, bleeding edge software like for a desktop. You would only implement and test the elements you really need. And there are real-time implementations of POSIX-like systems like QNX for example - and there software architecture is very much like Linux.
The real time perspective: Once Microsoft lost a competion at a steel manufacturers site because they couldn't explain how to handle a 50ton steel bar, moving at 6m/s with a software which reacts with a latency of 500msec.
At this point in time the bar might have punctured the next wall by 3m or so...
This simple fact is even more true for aviation.
Another argument is that aviation industry is conservative - most things which fly best are more then 10, often 40 years old.
And in this field it is often believed you cannot earn money with open source software - which is not true.
So many proprietary (and reliable) instruments are running on software from the nineties, i.e. many cash machines are still running on Windows NT derivatives.
Want to say: many instrument manufacturers are not willing to publish the source code of their well maintained software.
On the other hand: if Boeing had used open source software for their 737MAX, there is a certain probability, that the accidents wouldn't have happened.
And well, there you are: its all about testing in an acceptable amount of time.
No, more testing and even more testing....
And then you might end up with aviation-suitable software.
And for this, a real-time derivative of a POSIX software, would be a good if not even the ideal choice.

Hey, thanks for answering this old question of mine!  Which precise elements of QNX’ implementation of POSIX make it RT unlike a vanilla Linux? Also you state that their sw architecture is very much like Linux. This also implies there are differences. On which aspects do both operating systems (fundamentally) differ? (I haven’t had the chance to work with qnx)

"On the other hand: if Boeing had used open source software for their 737MAX, there is a certain probability, that the accidents wouldn't have happened." seems like a rather bold claim to make with no supporting evidence. Care to back that up?

Agreed, I don't see how using open source software would have reduced or prevented the accidents from happening.

There really isn't a need to have a commercial OS on avionics.
Avionics software tends to be designed for specific hardware - there is no generic hardware platform made in a mass market by a lot of vendors.
Avionics don't interact with a lot of other systems or hardware.
Avionics usually run as one application, so no need for timesharing or in the case of RTOS a guaranteed clock cycle schedule.
Those are the main purposes of an operating system as opposed to a simple bootstrap loader that loads up and starts one application - the operating system facilitates multiple hardware platforms, multiple drivers and utilities for disc/flash storage, timesharing with other applications, and peripheral devices such as networking. What avionics need to do: interact with the display, external sensors, and control buttons - don't have to involve an operating system.
An embedded OS is nice to have for a dedicated device, especially if the embedded application is going to publish  web services for external access and control. However, it is slower to load (could be a factor for avionics) and consumes more resources than a dedicated app that is fired up by a bootstrap loader.
Due to the extensive certification cycle, avionics don't tend to run the latest and greatest, nor do they have a short refresh cycle on the hardware.

There is no databus running on an aircraft, Arimc or Milbus, with multiple instruments running at different update rates, which need to receive and output their data at determined rates? Your imstrument runs entirely on its own, and the application is never ported to new hardware?


text:
After purchasing an aircraft, how do I put the transponder in my name?
I just purchased an aircraft and the prior owner said that I need to put the transponder to my name. What is the procedure to do that?

Welcome to aviation.SE! Which country are you in?

You need to look the transponder in the eyes and say out loud: "Luke, I am your father".

You'll know if that works if it changes to 7500 @GianniAlessandro.

If you are talking about a Mode S transponder, the ICAO 24-bit address assigned to it is associated with the aircraft’s registration. When you register your aircraft the Mode S registration is automatically transferred.

@JScarry, at registration a 24 bit address is assigned to the aircraft. Depending on the country of registration and whether the aircraft is transferred from the register of a different country, this may or may not be the same 24 bit address that was previously assigned to the aircraft. Therefore the Mode S transponder may need to be recoded with the new 24 bit address after the sale.

I assume you have a Mode S transponder. A Mode S transponder uses a unique 24 bit address assigned by the authorities to your aircraft to communicate with Mode S radars. If you do not have a Mode S transponder there is nothing that links your transponder to your aircraft registration.
If you purchase an aircraft you need to register it with the Civil Aviation Authority in your country. With that registration you will get a 24 bit address (in some countries you will always get it, in others you need to indicate that you have a Mode S transponder). The 24 bit address is usually given as a hexadecimal string of six characters, some countries use a 8 character octal representation. This code needs to be programmed in your transponder. It may be that the 24 bit address is the same as it was before. In that case nothing has to be done on the transponder.

In particular, in the U.S. the 24-bit address is deterministically derived from the N-number, so if the N-number doesn't change then the transponder doesn't need reconfiguring.  That's not the case in all (maybe even most) countries.

Standard practice or procedures involve the aircraft to be Register reserving their aircraft registration And also requesting their 24 bit or 6 Alfa numeric combination of 0 1 2 3 4 5 6 7 8 9 A B C D E and F into their physical transponder which the first 3 character is Country code and remaining 3 aircraft specific.
Example 8960F1 where 896 is country for United Arab Emirates and 0F1 aircraft assignment.


text:
How should you coordinate with traffic at non-towered airports?
I am a fairly new pilot. I recently flew to a non-towered airport in Quebec, Canada (Lachute, CSE4). There is a significant displaced threshold on each end of the runway. The airport has one taxiway which goes up to about half the length of the runway. Because the taxiway doesn't extend all the way, back taxi is required on one of the runways.
When I attempted to depart I noticed that all CTAF announcements were being made in French. Before I got to my holding point I had to cross the runway and I spoke in English before I did so. I do not speak or understand French. Once I got to the holding point I noticed two aircrafts which were performing touch and goes. There was really no time for an aircraft to takeoff before one of them would be on the base leg or the final. I waited for several minutes. I noticed another plane also waiting at another holding point. A third aircraft was taxiing and about to queue up behind me.
My question is:

What is the correct procedure in this situation? Do we continue to
wait until the other aircraft finish their touch and goes?
If there is no procedure defined (I'm not aware of any), what is
the correct etiquette in this situation?

After waiting for a while I waited for one of the aircrafts to take off. Then I immediately stated my intentions to back taxi on the active runway and started the back taxi. I saw the second aircraft turning from base to final and I accelerated towards the end of the runway and positioned myself towards the beginning of the runway/displacement threshold. There was no way I could have attempted a takeoff.
However, what I did made a number of people very unhappy and they berated me and told me that I should brush up my procedures (in English this time). I haven't come across this situation in my training. Can someone please help clarify the correct/accepted process?

Comments are not for extended discussion; this conversation has been moved to chat. If you wanted to answer, please use the answer box.

I think if you are flying in French speaking airspace, you should speak French.

@Cloud you are 100% wrong. English is the language of ATC across the entire world.

@Jamiec Sorry, I did not mean you should 'officially' be fluent. But like any non-native situation, knowing a few words could make all the difference and maybe people would respond better.

@Jamiec Also, French speakers are notorious for resisting when someone tries to force them to speak English. I'm not sure what it's like in Canada, but in France, you do not get a good reception if you just start barking in English at people.

If you get responded to by ATC in French, then the controller is breaking the rules.

With the airport markings, the displaced threshold beyond the runway is available for takeoff.
So I see the two possible intersection departures as: 2,682 feet and 3,607 (measured by google maps:)

.
You should've done an intersection depature.
Failing that, you can simply announce:
"N567 requires full length departure: Request that airplanes in the pattern extend their downwind while I back-taxi and depart"

Unless you are actually saying you were at the intersection right in the middle of the field, which is a poor choice, because it is clearly connected to the intersection near the departure end of 28.  You should've taxi'd over there on the taxiway, with no back-taxi on the runway.

Yes, the way it works on this airport is that you start on the right side of this picture, cross the runway and taxi towards the mid point. This is where I was holding short. There is no taxiway connecting this to the other holding point nearer the departure point for runway 10.

The problem with uncontrolled airports is that sometimes the procedures and "etiquette" can be informal.  The pilots based at the airport have established their own informal procedures which are not published anywhere or are part of any rule book.  In cases like this I would consult the FBO for the local procedures (which you did do) but that doesn't mean that all the pilots at the airport abide by them.  In your situation this is what I would have done:

I would have announced on the CTAF that I cannot speak French and would request that all pilots announce their intentions in English.  By international convention pilots are required to communicate to ATC via English unless there is an emergency.  However CTAF communications tend to be more informal and the pilots at the local airport may prefer to speak in the language they are the most comfortable.  Still the intent of CTAF is to communicate with everyone at the airport to announce their intentions.  It would have been entirely proper to request the pilots to speak in English.
I would have requested the pilots performing the touch and goes to give you a window in which to back taxi and takeoff.  I find it rather rude for pilots to monopolize the pattern and runway performing touch and goes.  If they see that there is a line of planes wanting to takeoff they should leave the pattern for a while and let folks takeoff before resuming their touch and goes.  Asking politely on the radio for these pilots to do this for you is reasonable.
If they were giving you grief for not using the grass to taxi to the runway they had no right to do that.  Taxing on grass can be dangerous especially in tricycle gear aircraft where the potential for a prop hit with the ground is a real possibility.  In my case I am bound by the club rules not to taxi on any surface that is not paved.  Back taxing would be the appropriate thing to do.

Thanks. All of this is good advice. I'm not exactly sure what they were unhappy about. Someone just came over the radio and said that I needed to 'Brush up my procedures'. I don't really know what exactly he was objecting to.

"By international convention pilots are required to communicate to ATC via English unless there is an emergency." I've never heard that one, and I'm pretty sure if it was the case, my radiotelephony instructor would have mentioned it. In the radiotelephony class I was in, we practiced communicating with ATC in both Swedish and English. The regulations here allow for both, and specify that the first call from the aircraft determines the language to use, though you need a separate theoretical and proficiency exam for each language privilege. Can you provide a reference for your claim?